Very interesting reading,
I also have a few 8088 games the will not run on
todays machines,mostly due the the hardcoded timeing
loops.
one would think that by now someone would write a cpu
slowdown pgm that does not affect the hardcoded
graphics code - like all the current ones do.
i have most of the ge numalogic "pc loader" for the
pc900 - pc1100 and the pc based programer for ge
series 6 model 60 plc's.
i also have to use a 486 and lower on the plc and
motorola radio programming software.
the reason that these programs will not run on a
faster then 486 (some only run releably on a 286)
is that the cpu speed runs the coded loops too fast.
that results in the pgm trying to read/write to the
device (radio or plc) faster then the programs i/o
instructions can respond.
i have had no trouble useing high speed serial ports
with the newer uart's.
the slowdown programs "time wasting cpu loop" does
slow down the program run, but the loop chops up the
i/o also and the devices always want 100% of the i/o
ports attenation - which results in the i/o loop being
droped and/or the program hanging or looping.
the problem could be a good one though, at least we do
have a use for the 8088's to 486's ;)
Bill
Message: 30
From: "TeoZ" <teoz_at_neo.rr.com>
To: <cctalk_at_classiccmp.org>
Subject: Re: Looking for a 486 system...
Date: Sat, 1 Mar 2003 12:00:32 -0500
Reply-To: cctech_at_classiccmp.org
Those packages have the same problems as older dos
games.
http://www.oldskool.org/pc/help/oldonnew/
"The second advantage is a natural resistance to
obscure programming
techniques, like self-modifying code. The 80386
doesn't have an
internal
cache like the 486 and higher, so most self-modifying
code works as
good as
it did on the original 8088."
I found alot of install routines written when the 386
was around would
cause
errors on faster machines because they hard coded
timer loops for user
input.
Since the PLC software uses the comm ports and they
are most likely
buffered
newer computers feed the data too fast for the serial
port.
One thing to try on faster machines is to disable
internal and external
cache in the system bios, then hit the turbo button to
slow the
processor
down to 8mhz (if possible)
If you really need a 386 motherboards with chip and
memory can be found
on
ebay really cheap, but are not too common. Buying an
old 386 from ebay
isn't
worth it because of the shipping costs of the heavy
boat anchors, but
motherboards are cheap. Getting a case from a local
thrift store to run
it
in wouldn't be too expensive.
----- Original Message -----
From: "James Rice" <jrice54_at_charter.net>
To: <cctalk_at_classiccmp.org>
Sent: Saturday, March 01, 2003 6:42 AM
Subject: Re: Looking for a 486 system...
> When I was working in process controls, we had PLC
programming
software
> from two different companies that would only run on
certain
processors.
> The original SLC-500 series software from
Allen-Bradley would not run
on
> a 486, but would scream on a 286 or 386. As soon as
you tried to run
it
> on a 486 or higher, instant crash, taking DOS
totally down to the
point
> only pushing the reset would reboot it. The PLC-2
series from ICOM
> would run on 8088-Pentiums, but faster than a 286
and the comm port
> control routines refused to communicate with the
system making it
> totally useless. There was a MMI package we used,
the names elludes
me
> (it's early) that wouldn't run if installed on a
hard drive over
240mb.
> It had a space checking routine that couldn't handle
hard drives over
> 240mb, or a processor over a 486DX25. It would
crash if either the
> drive was too large or if the system was too fast.
All of this
software
> was still current in 1994-98.
>
> As far as finding an older system, except for the
386 that is kind of
a
> museum piece, we scrapped eveything below 1ghz a
couple of months
ago.
Received on Sat Mar 01 2003 - 22:15:01 GMT